// FILE: bag4.h
// TEMPLATE CLASS PROVIDED:
//   Bag<Item> (a container template class for a collection of items)
//   The template parameter, Item, is the data type of the items in the Bag.
//   It may be any of the C++ built-in types (int, char, etc.), or a class
//   with a default constructor, an assignment operator, and operators to test
//   for equality (x == y) and non-equality (x != y).
//
// MEMBER CONSTANT for the Bag<Item> template class:
//   static const size_t DEFAULT_CAPACITY = _____
//    Bag<Item>::DEFAULT_CAPACITY is the initial capacity of a Bag that is
//    created by the default constructor. 
//
// CONSTRUCTOR for the Bag<Item> template class:
//   Bag(size_t initial_capacity = DEFAULT_CAPACITY)
//     Postcondition: The Bag is empty with an initial capacity given by the
//     parameter. The insert function will work efficiently (without allocating
//     new memory) until this capacity is reached.
//
// MODIFICATION MEMBER FUNCTIONS for the Bag<Item> template class:
//   void resize(size_t new_capacity)
//     Postcondition: The Bag's current capacity is changed to new_capacity
//     (but not less than the number of items currently in the Bag). The insert
//     function will work efficiently without allocating new memory) until the
//     capacity is reached.
//
//   void insert(const Item& entry)
//     Postcondition: A new copy of entry has been added to the Bag.
//
//   void remove(const Item& target)
//     Postcondition: If target was in the Bag, then one copy of target has
//     been removed from the Bag; otherwise the Bag is unchanged.
//
//   void operator +=(const Bag<Item>& addend)
//     Postcondition: Each item in addend has been added to this Bag.
//
// CONSTANT MEMBER FUNCTIONS for the Bag<Item> template class:
//   size_t size( ) const
//     Postcondition: Return value is the total number of items in the Bag.
//
//   size_t occurrences(const Item& target) const
//     Postcondition: Return value is number of times target is in the Bag.
//
//   Item grab( ) const
//     Postcondition: The return value is a randomly selected item from the Bag.
//
// NON-MEMBER FUNCTIONS for the Bag<Item> template class:
//   template <class Item>
//   Bag<Item> operator +(const Bag<Item>& b1, const Bag<Item>& b2)
//     Postcondition: The Bag returned is the union of b1 and b2.
//
// VALUE SEMANTICS for the Bag<Item> template class:
//   Assignments and the copy constructor may be used with Bag objects.
//
// DYNAMIC MEMORY USAGE by the Bag<Item> template class: 
//   If there is insufficient dynamic memory, then the following functions call
//   new_handler: the constructors, resize, insert, operator += , operator +,
//   and the assignment operator.

#ifndef BAG4_H
#define BAG4_H
#include <stdlib.h> // Provides size_t

    template <class Item>
    class Bag
    {
    public:
        // MEMBER CONSTANTS
        // enum { DEFAULT_CAPACITY = 30 }; // Or: 
	static const size_t DEFAULT_CAPACITY = 30;
        // CONSTRUCTORS and DESTRUCTOR
        Bag(size_t initial_capacity = DEFAULT_CAPACITY);
        Bag(const Bag& source);
        ~Bag( );
        // MODIFICATION MEMBER FUNCTIONS
        void resize(size_t capacity);
        void insert(const Item& entry);
        void remove(const Item& target);
        void operator +=(const Bag& addend);
        void operator =(const Bag& source);
        // CONSTANT MEMBER FUNCTIONS
        size_t size( ) const { return used; }
        size_t occurrences(const Item& target) const;
        Item grab( ) const;
        // FRIEND FUNCTIONS
        friend Bag<Item> operator +(const Bag<Item>& b1, const Bag<Item>& b2);
    private:
        Item *data;        // Pointer to partially filled dynamic array
        size_t used;       // How much of array is being used
        size_t capacity;   // Current capacity of the Bag
    };

#include "bag4.tem"  // Include the implementation

#endif